1. Field of the invention
The invention relates to a safety switching device for electrically controlled machines used in combination with the control elements of the machine control-system itself during hand or manual operation, in which the multi-action safety switching device has several channels or several switching circuits and the switching circuits have at least one operating element which can be adjusted by an operator depending on the desired switching function.
2. The Prior Art
Various safety switching devices, also known as starter switches, are already known. These starter switches are designed in the form of a plurality of individual make-and-break contacts arranged on spring contacts. Several operating members are assigned to these mechanical make-and-break contacts in order to adjust their position relative to one another and enable an electrical contact to be made or broken between two co-operating switch contacts. In order for these switch contacts to comply with the requirements placed on safety switching elements, a complex mechanism has to be provided to prevent specific inadmissible switching states. The disadvantage of the known devices is that these mechanical operating members require an expensive mechanical design in order to prevent inadmissible switching sequences.